On the evening of Thursday August 23d, I had an hour of clear skies, so I quickly got out with my Sky-Window and the 15x80 Vixen binoculars and the 85mm Zeiss refractor equipped with the 20-60x-zoom eyepiece. I wanted to have a look at an asterism called the Mini Coathanger (STAR 22 from Phil Harrington’s Small Telescope Asterism Roster) in Ursa Minor. The Mini Coathanger, which looks very much like his big brother the Coathanger in Vulpecula, can be found at RA 16:29.0 and DEC +80.13. I always start the search at 16 Zeta Umi. About 2 degrees northeast of this bright magnitude 4 star, a diamond-shaped group of stars can be seen. At the Northern tip of this diamond shaped group STAR 22 can be found. The Mini Coathanger is made up off 11 almost equally bright stars, most of them of the 10th or 11th magnitude. The asterism is 15’ wide. In the Millennium Star Atlas, the whole asterism can be found on page 1046.

That night, I started my observing session at 21.00 hours UT. The seeing from my backyard was only 5 on a scale of 10. Most bright naked-eye stars were blinking like crazy. The transparency and sky darkness weren’t too good either. I couldn’t see all seven stars of Ursa Minor, so the limiting magnitude was well below 5. However, with the 15x80 I quickly located the diamond shaped asterism, but the Mini Coathanger stayed invisible. After observing for a few minutes, I started to see a little bar of four or five stars, that form a part of the Mini Coathanger. The stars were very faint, and I could not see the complete asterism, not even with averted vision. Then I switched to the 85mm Zeiss. At 20x the bar of stars already looked a bit brighter, and seemed easier to identify. Zooming up to 60 times, using averted vision, I could see the whole asterism, the bar and hook. I could not detect any colour in the stars. After observing for 20 minutes from under a black hood, I could see the whole asterism with direct vision. I made the sketch below to using the 85mm refractor and the eyepiece at maximum zoom. The field of view at 60x is about 1.25 degrees, but I only sketched the central part of the field of view. Before I finished my observing session I switched back once again to the 15x80 binoculars. This time, using the black hood and averted vision, I still could not identify the whole asterism with the 15x80.

At 22.00 hours UT I packed up and went inside (had to work the next day), enjoyed my cup of coffee and put down a few notes. Looking back at the short observing session I can definitely say that the refractor with its 85mm aperture shows stars of the 11th magnitude much easier than the 15x80 binoculars. With the big binoculars, you use two eyes, which should compensate for the 5mm difference with the 85mm Zeiss. But in the end, I think that the higher magnification (you start at 20x with the Zeiss) makes the difference. The slightly higher magnification gives a little more contrast. If you zoom in to 60x, the 15x80 can in no way keep up with the views the refractor shows. However, I will try to hunt down all the asterisms on Harrington’s STAR list using both instruments. They are ideal for short observing sessions. Both instruments are mounted on video tripods permanently, so I only have to take them into the garden and I’m ready to go!

At the border of Cassiopeia and Cepheus, near M52, a whole group of open clusters can be found. One of them is the magnitude 9.2 NGC 7510. Last Saturday, August 11th 2007, I decided to revisit this small, (6’ in diameter) open cluster, and make a sketch at the eyepiece.

Image from "Where is M13?" by Think Astronomy

To observe NGC 7510 I used the 300mm Dob with the 21mm Denkmeier, the 12mm Nagler and the 7 and 5mm Pentax XW. After locating it with my Argo-Navis, I immediately recognized the small and rich open cluster, even with the lowest magnification (76x). The familiar arrowhead shape is something you will not forget, once you’ve seen it. At first glance, NGC 7510 looks very small indeed. This is in part because of its distance. NGC 7510 lies in the Perseus Arm of our galaxy, approximately at a distance of 10.200 light-years. This makes it one of the more distant open clusters. However, would you place NGC 7510 at 440 light-years, where we find the Pleiades, it’s apparent size would be 1.55 degrees! It would 30% larger than M45.

After increasing the power to 320x (5mm Pentax) I noticed that a lot of stars I’d seen on previous occasions stayed invisible. In fact, the transparency proved to be horrible. When comparing the sketch with a printed map from SkyTools2 the next day, the faintest star I plotted using my 12-inch scope was only magnitude 13.3. From the same location, my own backyard, I reached magnitude 13.5 with the 8-inch TAL 200K, on a very good night a few years ago.

Anyway, I made a sketch at the telescope with just a HB pencil, eraser and a piece of sketching paper. I did not plot all the field stars. I only concentrated on the possible cluster members. It is always very hard to recognize the real border of a cluster, and to determine which stars do belong to the cluster and which don’t. But I’m not the only one! When checking different entries in my observing guides I noticed that the values for size, numbers of stars and even magnitude vary a lot from one another. The eyepiece used for the sketch was the 5mm Pentax XW (320x). It took me 45 minutes to observe NGC 7510 and to complete the rough sketch. The next morning, with the help of my rough sketch and the notes I recorded on my Ipod, I made a new, final sketch to file in my observing log. For this final sketch (see image below) I used black paper and very a very soft white pencil. I only plotted the stars I had on my original sketch. I used a printed map from Skytools2 to check the positions of the stars and to the check the limiting magnitude for that night.

As you can see, I counted about 19 stars in the cluster. There was no real color visible in the stars, though I suspected a little color in the brightest. It seemed a bit yellowish, but I must have been wrong because when checking my observing library, I found out that its Lucida is a luminous blue B1.5 III giant (Sky Vistas, page 78, Crossen and Rhemann). The sketch is made with north up and east is to the left.

Last Saturday I had a great time together with Leo. Together we observed not only some well-known deepsky objects, but also a few "new" objects. I used my 300mm Dob and got a chance to test my two new eyepieces, the 21mm Denkmeier and the 5mm Pentax XW. Leo observed with the TAL 250K. The outside temperature was between the 15 and 20 degrees Celsius. The seeing was average, but the transparency was not too good. We barely could make out all the 7 stars of Ursa Minor. But after months of rain and clouds, you are happy with every observing opportunity, so we took it with both hands. The waning last quarter Moon came up around 00.00 hours and stayed out of the way (behind some trees) until 03.00 hours. Anyway, we had a good time observing the deepsky from 22.30 until 03.00 o' clock.

Polaris
In the low light of dusk we started of with a one of my favourite double stars, Polaris. What struck me was how easy it was "to see" the double in both telescopes. The white B component was very easy to see, next to the yellowish A component. The separation is a generous 18", but I always have to take a good look to see the B-component. Later that night we revisited Polaris and it was a very different story. The 2nd magnitude A component almost completely outshone its magnitude 8.2 companion. Of course it was a lot darker later in the evening, during our second visit of Polaris, so the difference in brightness was much more apparent than earlier on.

16 Cygni and the blinking planetary (Caldwell 15)
The next stop was another nice double, 16 Cygni, which had a companion in the same field of view, NGC 6826 (The Blinking Planetary). 16 Cygni consists of two yellow-golden suns of almost equal magnitude, separated about 40" from each other. About 30' to the northeast of 16 Cygni I spotted the Blinking Planetary. In the 21mm Denkmeier with a field of view of 51' it was easy to get this bright planetary nebula into the same field of view with 16 Cygni. A nice couple of objects to look at. It is a very strange experience, watching the Blinking Planetary. If you look straight at the central star (which is visible even at the lowest magnification of 76x) the nebula seems to disappear. However, if you look a bit to the left of the Blinking Planetary, using averted vision, it pops into view.

I tried several magnifications (76, 133, 229, 320) but the blinking effect disappeared at 320x This was for me the optimum magnification to look at the nebula. It was perfectly round and I could detect no real areas of uneven brightness, and there is no well-defined sharp edge to the nebula. It showed only a hint of bluish-green colour tonight. It was very difficult to really "see" the colour. The OIII filter killed all the stars in the field, so I switched to the UHC narrowband filter. This enhanced the contrast a bit but I still like the view without filter most.

T Lyrae (Carbon Star)
Again a star that surprised us. Last year we have been looking for it with the 10-inch TAL but only after increasing the magnification to 200+ we could find it. It was very dark red and almost invisible at lower magnifications. Last Saturday I pointed the 12-inch dob at the location where I should see T Lyrae, and there it was. Not dark red and invisible but very bright and intensive orange. This is the first variable star that I have ever observed near its minimum and near its maximum, and I must admit, it's a great experience. I never imagined that two magnitudes could make such a huge difference in visibility.

Image from Skytools by CapellaSoft

Phil Harrington's STAR 22, the mini-coat hanger
Next on the list were three objects from Phil Harrington's STAR list (Small Telescope Asterism Roster). The first to visit was the Mini-Coat hanger in Ursa Minor. It looks like a smaller version of Collinder 399 in Vulpecula, the (big) Coat hanger. It is made up of 11 stars and the diameter is about 30'.

Phil Harrington's STAR 23, the backward S and STAR 24, a conspicuous ring
These two asterisms can be found in Hercules. I just had a quick look, but all three STAR's from Harrington's list will be revisited for a closer examination and a sketch. At this point we went indoors for a short break and some refreshments.

Double Cluster (Caldwell 14)
After the break I turned my telescope towards the Double Cluster in Perseus, NGC 869 and NGC 884. In the Dobson I immediately noticed a difference with my 8-inch TAL. The colour in some stars was much more obvious in the 300mm Dob. At lowest magnification, 76x, I noticed three bright yellow stars among all the blue/blue-white stars of NGC 884. When checking with my observing bible, "The Night Sky Observers Guide", I got confirmation of my observation. Three red super giants can be found in NGC 884.

The screaming owl
This is not some obscure asterism, but something that scared us like hell. Around 1.30 on Sunday morning a large bird, with a wingspan of two to three feet, flew over us screaming like the devil himself was on his heels (or tail actually). After little investigation on the Internet it proved to be a Barn Owl. Wow, what a sound! Turn up the volume real loud and .........Click on this link to get an idea......but be warned, this is not for the faint-hearted!

And here is an image of this wonderful bird.

Click to enlarge

NGC 7510 and Markarian 50
After we managed to get our heartbeat down to a normal rate again, we moved to our next stop, two open clusters on Perseus-Cassiopeia Border, NGC 7510 and Markarian 50. NGC 7510 is a lovely object, even at low power. It looks like a kind of arrowhead at 76x. I liked the cluster best with the 5mm Pentax, magnification 320x, FOV 13'. The cluster is only 4' in diameter so there's plenty of room left in the field of view. I counted about 25 brighter and weaker stars that where arranged in a kind of small circle with three legs dangling from the circle. In fact it looked like an octopus! I could detect no background nebulosity and no coloured stars. Next stop was Markarian 50, but this cluster proved to be almost invisible tonight, so we will try it on a night with better transparency and sky-darkness.

M52, Czernik 43, and NGC 7635 (Bubble Nebula, Caldwell 11)
From the invisible Markarian 50, it was only a small step to a very interesting trio, just across the border to Cassiopeia. You can get two open clusters, M52 and Czernik 43, and an emission nebula, NGC 7635, into one field of view. M52 is a very irregular cluster without a real shape, while Czernik 43 looks much more organized, a kind of large triangular shape with 4 bright stars on a row on one side of the cluster. The Bubble nebula was only visible with the highest magnification and averted vision. With direct vision it stayed invisible. This is an object which we have to revisit under better conditions (no Moon, better transparency and darker skies).

At 03:00 we ended our observing session. We saw quit a few wonderful objects tonight, but for me the one thing I will remember is that impressive large bird, breaking the silence with its very harsh call. It was very special to see him soaring through the night sky, only lit by the light of the Moon. It was the first time ever I saw a barn owl and I hope I will see one again somewhere in the future. « Collapse

On Saturday July the 15th, Leo and I finally had a good evening of observing together. We enjoyed hunting some deep-sky objects, he with the 4-inch Takahashi and I with my 15x80 Binoculars mounted on the SkyWindow. We started of with two very large clusters near the Serpens Cauda / Ophiuchus border, NGC 6633 and IC 4756. These two contrasting clusters are also included in O'Meara's "Hidden Treasures", under the numbers HT 92 / HT 93. With my 15x80 binocular (field of view 3.5 degrees) I could not see both clusters together. I had to turn the SkyWindow from left to right and back again to compare both clusters, but I noticed immediately how different these two open clusters are. I estimated IC 4756 about 45' or 50' in diameter. In a trapezium of 4 bright stars I count at least 50 weaker stars. NGC 6633 looks much more compact, about half the size of IC 4756. However, the individual stars are brighter, and are grouped in a kind of small elongated circle, and a few long straight streamers of stars. These two clusters are wonderful objects for binoculars.

Our next stop was Phil Harrington's STAR 26 ( STAR=Small Telescope Asterism Roster), the Red Necked Emu in Cygnus, The Swan. I had seen it once before in my 4-inch refractor a few years ago, so I knew what I was looking for. The Red Necked Emu looks like a giant propeller with three blades, about 1 degree in diameter. Just start at Gamma Cygni, the orange star at the heart of Cygnus, and move towards Albireo along the neck of the Swan for 2.5 degrees to 34 Cygnus. From there move about 1.5 degrees in the same direction to arrive at 29 Cygnus. This star marks the tip of the Emu's tail. On the image below you can see how the Emu is oriented in the sky. Through my 15x80 it was very simple to find. I think this object is best in 80 to 100 mm instruments, with a large field of view. This strange bird is called Red-Necked Emu because all the stars he consists of are white-bluish, except one orange-reddish star in its neck. This is very easy to see.

Click to enlarge

After this I first freewheeled a little through the Milky Way in Cygnus, a wonderful experience with binoculars. M 29, Albireo, Omicron 1 and 2, are just a few of the stops I made. After that I also made a little tour through Vulpecula: The Coathanger (Collinder 399) The Dumbbell (M 27), and the wonderful open cluster NGC 6940. Although not very well resolved, NGC 6940 stood out well from its surroundings, however I like this object more in my 300mm Newtonian. From Vulpecula I turned back again into the Swan, passing M 39 and on to Mu Cepheus, the Garnet star. In this area we looked at a few open clusters, but because we had some problems identifying them, we will have to revisit this area.

Last night it was clear between 11 and 1 o clock (local time) and I had a quick look at some deep-sky objects with just to test my new eyepiece, the 21mm Denkmeier. In my dob, the 65-degree eyepiece gives a magnification of 76x and a true field of view of 51'. I pointed the eyepiece at M 27 and although it wasn't really dark (grey nights during the May-July period), it was quite an impressive sight. M 27 is really big, even at low powers, and with the UHC filter the Dumbbell shape is very obvious at first sight. The 21mm Denkmeier seems to be very "transparent", letting through much more light than the 20mm and/or 25mm Vixen Lanthanum. The stars where sharp right to the edges although I think that there is a little pincushion distortion along the edges. What I really love about this eyepiece is the generous 20mm eye-relief. Even with my glasses on, I can take in the whole field of view at once.

The second object for the night was M 13, the big globular cluster in Hercules. The 21mm showed too much of the grayish sky, but M 13 was already resolved very well. The best view I got with the 7mm Pentax XW (230x). The cluster was completely resolved, even under these mediocre conditions. There were a lot of long streams of stars extending from the bright core. It looked more or less like a big spider. The three dark diverging lanes, which should look like a propeller, stayed invisible again. Probably I need a better seeing and a darker sky for this.

After M 13 I turned the dob toward NGC 6210 (Hidden Treasure 78 from Stephen J. O'Meara's book, Hidden Treasures). Already at the lowest magnification (76x) with the 21mm Denkmeier, this planetary Nebula looks like a deep-blue little disk. Using higher magnifications up to 230x made it look a lot bigger, still blue, but not so blue as with the lowest power. The seeing didn't allow higher magnification, so I could not go for the real details. According to Phil Harrington (The Deep Sky: An Introduction) this planetary takes high magnifications well, and is at its best 150x or more.

I ended my little tour with two objects I had never observed before, Hidden Treasure 94 (The Flying Unicorn Cluster) and Hidden Treasure 18 (The Ghost of the Moon) from the Additional list from O'Meara's latest Deep-Sky Companion. HT94 (NGC6709, Collinder 392), the Flying Unicorn Cluster, is a wonderful open cluster in Aquila. At low powers (78x) the triangular shaped cluster is very obvious, with some very nice groupings of (colored) stars. Although high magnification (230x) revealed more stars, I liked it most in the 12mm Nagler with a magnification of 133x. The cluster was nicely framed, some 40 to 60 stars with some "space" left around it. The colors came out even better than with the low power view, and I could detect quit a few "double-stars" or groupings of several stars; a very nice object, which I will definitely visit again under better conditions.

HT 18 (NGC 6781) from Appendix C (Twenty additional hidden treasures is) is a magnitude 11 planetary, about 2' in diameter. Without filters this big planetary is not so easy to see, but with the UHC filter in place it is a perfectly round, very bright and easy object. There should be some details visible at higher magnification, but because of the bad viewing conditions I did not try this last night, but again a very interesting object, which was completely unknown to me. At the moment this hidden treasure list is my favorite a perfect alternative for those who have done the Messier and Caldwell catalog. I will be back with more observing details on these interesting deep-sky objects, but I will need a darker and more stable sky. Until then, Clear Skies to all of you!

Oh, and the Denkmeier eyepiece is a perfect match for my 300mm f 5.3 dob. If you wear glasses or want a good eye-relief for any other reason, I can highly recommend this relatively small and compact eyepiece.

A few weeks ago I got a new book from Steven James O-Meara: “Hidden Treasures”. This is his third Deep-Sky Companion he wrote and it is definitely my favorite read at the moment. After the well known “Messier Objects” and “Caldwell Objects” this new book, Hidden Treasures, is again about 109 deep-sky objects, but this time about objects which are not included in the Messier or Caldwell catalogs. Some of them are well known, but there are a lot of objects which were more or less new to me.

Again the whole range of deep-sky objects is included, Galaxies, Planetary Nebulae, Star Clusters (open and globular), Asterisms, Bright Nebulae, Dark Nebulae and even a High-proper motion star. Steven James O’Meara is getting better and better. I like the way he writes his deep-sky companions. There’s always a lot of information about each individual object (history, observing the object, how to find it, and up to date scientific information), and for every object a finder-chart, black and white image and a sketch. The information you get in this book is also fully consistent with the two other books in this collection.

I can highly recommend all three of them. In the English language, they are by far the best observing guides around at the moment, and Hidden Treasures is with almost 600 pages packed with information on 109 deep-sky objects the crown on this wonderful series (until now).

During the last few weeks the weather hasn’t been very kind on the observing front, so I cannot bring you much news about deepsky, solar or lunar observing. Most of the time it has been cloudy or completely overcast. Monday night however the clouds opened up for an hour, and I got a quick glimpse of the Moon with my binoculars. This image of the Moon was taken just a mile from where I live near the water tower.

Last week we were walking through the fields in our hometown. As you can see on the image below, about an hour before sunset we were treated on a very special sight, the Sun “touching” the top of a big cloud. The view instantly reminded us of Mount Doom, the big volcano in Mordor (from The Lord of the Rings). Hmmmm….. maybe finally something happening in Landgraaf, Netherlands